I need help with a charging issue on my 79 Mini. I have had the alternator tested and it tested fine. There is a volt guage and an amp gauge attached and they both dont show any movement at all unless starting and then the amp gauge pulls way down. The battery seems to discharge and I can start the car only a few times before it won't crank and I will have to recharge the battery. The starter will crank very slow even when charged but tapping it a few times will usually get it to where it will crank quickly and start the car. It is a high compression engine and hot starts are a real pain. I hope someone can make suggestions about the charging issue. I hooked a separate volt meter to the battery this weekend and it showed 12 volts even when running and reving but would occasionally spike 14 for a split second. HELP!

 

This sounds like a problem.

Has this problem happened before? Or is it new?

 

It has had this problem since purchased. Owner told me that the car needs to be driven to keep the battery charged up, which should have been a warning that this was an issue of some kind.

 

The battery might be bad.
Even if the battery shows 12V it might not have the capacity to run the system. Think of a thimble full of water and a gallon of water, both are full but have very different capacities.

I don't have much experience with starter motors, but having to tap it to get it to work doesn't sound good.

 

When I said tap, I meant turning the ignition key and tap it over until it would crank quickly. I really think the main problem with the cranking issue is too much advance and simply checking and probably retarding the timing slightly will eliminate the hot starting issue. It only happens after engine is at operating temp. The charging issue is causing me the most problem. The previous owner said the battery was new but I should have it checked just in case there is a bad cell (even though I think I did this already, too many toys cant remember).

 

That makes a little more sense, I would check the battery

 

and the timing

 

Random thoughts here. First you have to turn the ignition on and off a few times to get it to crank quickly? meaning you are charged up to allow it to make a rapid cranking effectively helping to get it started? Then you have also issues with charging. First, the battery maybe at fault in what others have said. 2nd if this is a higher compression engine and needs more amps to start, the battery cable maybe too small to handle the load. Does the starter cable get very WARM when you attempt to start? if so you may need to use a larger gauge wire cable (depending on what you have now?).
Also ensure that the starter is shimmed properly. It when HOT maybe misaligned and causing some issues. Also if the windings are weak when it gets WARM/HOT it takes more energy to start, causing issues with the starting circuit and this can also in turn cause the battery to be killed quicker. So my suggestion FWIW...replace the battery with a NEW one (or borrow one if you can?) install a NEW started (one that has been WELL bench tested) and larger gauge starter cable. I assume you checked the voltage regulator? it should be putting out about 13.3-14.5 Volts. I am not sure on Mini (original) but in many euro cars it is not part of the alternator/generators!!!

Good luck hope some of this helps.

Regards

Scott.

 

Those are some good thoughts regarding my starting issues. I really appreciate the help from everyone.

 

Starters sometime get dead spots in the contacts. A new set of brushes in the starter motor may help. A starter and alternator shop could take a look at it and determine if the motor needs rebuilt.

I'd invest in a battery tender if you are not driving it alot. I just picked one up at walmart for less than 20 bucks. The battery drains over time and basically the tender monitors the batterys charge capacity and charges it as needed. Car batterys like to be fully charged all of the time to make them last.

 

Good tip on the starter even though I really think its a advanced timing issue. I do have a battery tender on the car at all times. It starts and runs fine, its just that after a few starts the battery is dead enough that it won't start. I am thinking more and more from the excellent posts that indeed it may be a battery issue along with too small cables that may be causing me problems keeping a charge.

 

Cootie --

If the engine is running and the battery is fully charged, a voltmeter gauge should read around 13.5 volts. If the engine is running and the voltage of the battery is only 12 volts, the battery is not fully charged (or is faulty). For reference, when my engine is stone cold (like after sitting overnight) the voltmeter reads 12.5 volts before cranking the starter. After the engine starts, the voltmeter reads 12 volts for 3 or 4 minutes while the battery is recharging, then reads just over 14 volts from then on. Oh, and the values are read on an AutoMeter aftermarket gauge.

My 1275 has 10.1:1 compression and cranks over (hot or cold) no problem with stock starter, stock alternator, stock battery cables, and an optima red top gel-cell battery. I agree with previous posters that you should check your starter brushes. I don't agree that you should start swapping out battery cables, as the stock cables should be sufficient for starting a Mini engine (although a visual inspection to make sure the cables are not damaged is a good idea). Another thing to check is electrical grounds (engine to body, body to subframe, and subframe to engine). Mine has all three. Grounding issues can cause very strange behavior.

Is the starter excessively hot after the engine is running for a while? If the starter is very hot (for some reason) after driving the engine, the starter will obviously have poor performance, with similar results that you're seeing.

Another thing to try is to start your mini engine using jumper cables from another car, both with the engine cold and engine hot. This may aide in determining whether the battery and/or cables are the issue.

Good luck, and make sure you post what the fix is when you find the problem.

Cheers,
Jeff

 

I'd start WAY on the simple side cuz my 79 acted like this when I got it and the problem ended up being a ground problem

1. Check the ground at the battery, be sure you have clean metal to metal contact at all connections.

2. Check the starter relay...be sure all the connections have clean metal to metal contact.

3. Ditto the starter

4. Finally find the engine block strap...

this one was my problem....mine ran from the enginge stab' on the block to the corresponding stab' block on the body. 'cept it connected to the bottom of the stab' brace....and the bottom bolt was loose. So the strap hung loose also. I could trun the key and get a weak turn, cuz the strap had poor contact. Bump a time or two and the strap would jump to better contact.....them Zaroom.

Once found, tightening the bolt has solved the prob' for the last 5 years......

Oh...mine had a "brand new battery" when I bought it. 6 months later I went to the source store asking for a check.

"Did you get 20 starts out of it?"

Seems it was brand new....and the cheapest battery they sold. They were surprised it had lasted a year. On a warranty pro-rate I could get less than $10. A new OPTIMA and cleaning all connections help a TON.

 

My battery was reading 12 volts at the battery regardless of started or not. What seems unusual was that every few seconds the volt would spike to 14-15 for a split second.

 

That is a good suggestion regarding the grounding straps. I honestly don't remember seeing a strap from the engine to the frame. I will have to check that out. Thanks, Keith